In order to improve their game, golfers often customize their equipment to fit their particular swing. Absent a convenient way to make heads and shafts interchangeable, a store or a business offering custom fitting must either have a large number of clubs with specific characteristics, or must change a particular club using a complicated disassembly and reassembly process. If, for example, a golfer wants to try a golf club shaft with different flex characteristics, or use a club head with a different weight, center of gravity, or moment of inertia, in the past it has not been practical to make such changes. Golf equipment manufacturers have been increasing the variety of clubs available to golfers. For example, a particular model of a driver-type golf club may be offered in several different loft angles and lie angles to suit a particular golfer's needs. In addition, golfers can choose shafts, whether metal or graphite, and adjust the length of the shaft to suit their swing. Recently, golf clubs have emerged that allow shaft and club head components, such as adjustable weights, to be interchanged to facilitate this customization process.
One example is U.S. Pat. No. 3,524,646 to Wheeler for a Golf Club Assembly. The Wheeler patent discloses a putter having a grip and a putter head, both of which are detachable from a shaft. Fastening members, provided on the upper and lower ends of the shaft, have internal threads, which engage the external threads provided on both the lower end of the grip and the upper end of the putter head shank to secure these components to the shaft. The lower portion of the shaft further includes a flange, which contacts the upper end of the putter head shank, when the putter head is coupled to the shaft. This design produces an unaesthetic bulge at the top of the shaft and another unaesthetic bulge at the bottom of the shaft.
Another example is U.S. Pat. No. 5,433,442 to Walker for Golf Clubs with Quick Release Heads. The Walker patent discloses a golf club in which the club head is secured to the shaft by a coupling rod and a quick release pin. The upper end of the coupling rod has external threads that engage the internal threads formed in the lower portion of the shaft. The lower end of the coupling rod, which is inserted into the hosel of the club head, has diametric apertures that align with diametric apertures in the hosel to receive the quick release pin.
Another example is U.S. Patent Pub. No. 2006/0105855 A1 to Cackett et al. for a Golf Club with Interchangeable Head-Shaft Connections. The Cackett publication discloses a golf club that uses a sleeve/tube arrangement instead of a traditional hosel to connect the interchangeable shaft to the club head in an effort to reduce material weight and provide for quick installation. A mechanical fastener (screw) entering the club head through the sole plate is used to removably secure the shaft to the club head.
Still another example is U.S. Pat. No. 6,547,673 to Roark for an Interchangeable Golf Club Head and Adjustable Handle System. The Roark patent discloses a golf club with a quick release for detaching a club head from a shaft. The quick release is a two-piece connector including a lower connector, which is secured to the hosel of the club head, and an upper connector, which is secured to the lower portion of the shaft. The upper connector has a pin and a ball catch that both protrude radially outward from the lower end of the upper connector. The upper end of the lower connector has a corresponding slot formed therein for receiving the upper connector pin, and a separate hole for receiving the ball catch. When the shaft is coupled to the club head, the lower connector hole retains the ball catch to secure the shaft to the club head.
However, the utilization of pins, screws, and/or coupling rods in the attachment of the shaft to club heads has certain drawbacks. The addition of these connection aids may add weight to the clubs, which negatively affects swing speed and moments of inertia, and therefore overall club performance and ball-striking ability. Furthermore, these methods take time to attach and detach. Finally, these connection aids are subject to stripping and/or material failure if exposed to excessive forces either during attachment or during normal club use.
Hence, there remains a need in the art for golf clubs with an improved connection that provides a method for quickly and easily interchanging the shaft, removable weights and other attachments with the club head.